Search for photoproduction of axionlike particles at GlueX

We present a search for axionlike particles, $a$, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the $a$-gluon coupling is dominant. The search uses $a\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ and $a\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ decays, and a data sample corresponding to an integrated luminosity of $168\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ collected with the GlueX detector. The search for $a\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ decays is performed in the mass range of $180<{m}_{a}<480\text{ }\text{ }\mathrm{MeV}$, while the search for $a\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ decays explores the $600<{m}_{a}<720\text{ }\text{ }\mathrm{MeV}$ region. No evidence for a signal is found, and 90% confidence-level exclusion limits are placed on the $a$-gluon coupling strength. These constraints are the most stringent to date over much of the mass ranges considered.